Electrically-operated portable drill.



PATENTED JAN. 9, 1906.

A. PEDERSEN. ELBOTRIOALLY OPERATED PORTABLE DRILL.

APPLICATION FILED SEPT.19, 1904.

2 SHEETSSHEET l.

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PATENTED JAN. 9, 1906.

A. PEDERSEN.

ELEGTRIOALLY OPERATED PORTABLE DRILL.

APPLICATION FILED SEPT. 19, 1904.

2 SHEETSSHEET 2.

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UNITED STATES PATENT OFFICE.

ADOLPH PEDERSEN, OF CLEVELAND, OHIO, ASSIGNOR TO THE VANDORN- ELLIOTT ELECTRIC CO., OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

Specification of Letters Patent.

ELECTRlCALLY-OPERATED PORTABLE DRILL.

Patented Jan. 9, 1906.

T0 all whom, it may concern:

Cleveland, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in Electrically-Operated Portable Drills, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

My invention relates to portable drllls, and particularly to electrically-operated portable drills, its object being to provide a machine of said aforenamed character which will embody economy in construction and operation and safety in manipulation.

The said invention consists of means hereinafter fully described, and particularly set forth in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings, Figure 1 represents a vertical axial section of an electrically-operated portable drill embodying my invention, the drill-spindle being shown therein in elevation and the shank of the drill being shown located in such spindle. Fig. 2 represents a plan view of said structure, showing the top cap or head removed, the operating-handles being shown as broken away. Fig. 3 represents a deta led side elevation of that portion of the dev ce embodying the controlling-handle and the electrical controller and safety mechanism governing the action of the motor. Fig. 4 represents a plan of the removable end cap or head of the casing inclosing the mechanism of the drill. Fig. 5 represents a cross-sectional view of said head, taken upon the plane indicated by line V V of Fig. 4.

My improved construction embodies an outer casing A, made of magnetic material, such as cast-steel, comprising a main portion a, a lower end cap or shell a, permanently attached to the main portion a, an upper removable head a and a lateral removable portion a inclosing and carrying the controller and safety devices previously mentioned. This portion a is provided with an integral projection a", whose inner surface forms a bearing for the operatinghandle B. Diametrically opposite the projection a and formed integral with the main portion a of the casing is a second projection a, into which is screwed a second handle B, the latter being immovably secured to said projection. As shown in the drawings, the axes of these handles B B lie in the same straight line. The lower portion a of the casing is provided with a hollow centrally-located portion a, in which is secured a bushing a],

forming a bearing for the drill-spindle C.

This spindle projects upwardly into the casing and is formed with a collar 0 intermediately of the ends of the spindle, the upper or inner end of the latter being of reduced diameter, as shown. Upon the spindle intermediately of the flange c and the bushing a is keyed a spur-gear D, which meshes with two pinions d d, located diametrically opposite each other within the casing, as shown in Fig. 1. These pinions are secured to the lower ends of two short pintles e e, which are j ournaled in vertical bearings ff, formed in a transversely-located diapln'agm F, which is secured between the upper casing portion a and the lower casing portion a, as shown in said figure. To the upper ends of these pin tles are respectively secured two gears c c, which mesh with the pinion E, keyed to the lower end of the hollow motorshaft G. The lower end of this shaft is provided with a cone g, which bears upon antifriction-balls g, the latter traveling in a raceway f, secured in a suitable seat f formed in the central part of the diaphragm F. The upper end of the motor-shaft is provided with a cone g bearing upon antifriction-balls g-, which travel in the raceway a, secured to the central part of the removable head a Coaxial with and located within the hollow shaft G is a feed-screw H, comprising a male member H and a female mem ber H the latter projecting through a central opening a formed in the center of the removable head cf, the upper end of said member being provided with a handle it and a conical centering-piece h. The lower end of said male member H projects below the lower end of the shaft G and is formed with 105 an end bearingh for receiving the upper end of the drill-spindle C. Secured to the lower end of this member H is a ball-race member 7L3. Disposed opposite said member and secured to the drill-spindle is a second race member 0, the two members forming a raceway for a series of antifriction-balls 0 The member 0 is seated so as to bear against the flange 0, previously referred to, as shown clearly in Fig. 1. It will thus be seen that an antifriction thrust-bearing is formed for receiving the thrust due to the feeding action of the feedscrew when the device is in operation. Secured to the central portion of the shaft G is the armature G of a multipolar series-wound constant-potential electric motor, the poles being four in number in the device illustrated. The pole pieces G of the field structure surrounding the armature are secured to the inside of the casing by means of screws a".

The removable head a is provided with four bolt-holes a located ninety degrees from each other, through which extend binding-bolts J, whose inner and outer ends are threaded, the inner ends extending through the diaphragm F. These bolts pass through the casing between the field sections, as shown in Fig. 2, and are provided with nuts at their respective ends which engage the dia phragm and removable head, respectively, as shown in Fig. 1, thereby securely fastening the head in place, as will be readily understood. Wound upon each bolt is a resistancecoil K, such coils forming a series of resistances properly connected with a controllerarm and contacts hereinafter described, whereby such coils may be thrown into and out of the circuit to vary the speed of the motor, as will be readily understood. This arrangement of resistance-coils, it will be seen, is very convenient and compact and does not necessitate the provision of a separate compartment or space for the necessary resistance. This feature of construction adds materially to the economy of the arrangement and construction of the mechanism. Secured to the head a in any suitable manner so as to project from the inner surface thereof are two studs (1 a upon the inner ends of which are respectively secured brush-holders e (L12. That portion of the head to which the studs are secured consists of a ring a, provided with an inner circular boss seated in a circu lar aperture a formed in the main portion of the head (L The said ring a is provided with'a series of elongated segmental slots a, through which pass binding-screws a by means of which the ring may be fixed relatively to the main portion of the head. By means of this construction it will be seen that the ring, and hence the brushholders, may be caused to assume various positions around the line of the motor-axis and that variations in the adjustment of the brushes upon the commutator G of the motor may be effected.

This commutator is secured upon the motorshaft in the usual manner and as illustrated in Fig. 1.

As before described, the operating-handle B is rotatably mounted upon the casing por tion a". The inner end of said handle projects into said casing portion and is of a reduced diameter, as shown in Fig. 1. Between the extremities of this reduced portion is loosely mounted a disk I), provided with an aperture 1). Below this disk I) is rotatably secured to said reduced portion a second disk 6 which is similarly provided with an aperture 72 Secured to the inside of disk 6 is a spring member 6 provided with a stud 6 which normally projects through the aperture and a short distance into the aperture 6. It will therefore be seen that when the parts are in this described position the disk I) is rotatably secured to the handle B, so as to turn therewith and with the disk I)". Aspiral spring b( shown in dotted lines in Fig. 3) is secured to the disk I), and fixed to the latter is a contact-segment N, which is adapted to contact one or more of a series of contacts Ir, (shown in dotted lines in Fig. 3 and in full lines in Fig. 2,) the latter being suitably connected with the resistance-coils in the manner usually employed in the constructimi of controllers. The spring I) is so arranged that when the pin is out of engagement with the aperture 1) said disk I) will be moved by spring I) so as to cause the contact-segment 1) to disengage the contacts 7r-that is, cause said segment to assume its off position, in which no current is permitted to flow through the motor -circuit. Passing through the main casing portion a and screwed into the pole-piece G adjacent to the casing portion a and having its outer surface lying in proximity to the path of travel of the spring member I) is an iron member M. Such construction, it will be observed, will render this member M magnetic when the pole-pieces are magnetized by the flow of current through the motor-field. Secured to the handle B and rotatable therewith is a member N, formed with a bottom flange n, having formed in its periphery a notch n, the latter being out upon the arc of a circle. Adjacent to said member is a n1anually-operated switch 0, arranged to reverse the current through the motor. This switch is provided with a circular flange 0, in which is cut two notches 0 0, the latter being out upon the arc of a circle substantially equal to that defined by the circumference of the flange a of the n1e1n ber N. The are upon which. the notch. a is cut is that of a circle substantially defined by the circumference of the flange 0 of the switch. The location of the notch n is such that when the controller is in its off position said. notch will be located opposite the flange 0. It will therefore be seen that when these parts occupy such last-described. position the reversing-switch may be operated and that when the controller contact-segment is in a position such as to permit current to flow through the motor the reversing-switch cannot be operated and is locked in place. This prevents the reversal of the current while flowing, and thus prevents damage to the electrical mechanism.

The above-described mechanism operates as follows: Current being sent through the motor by turning on the controller contactsegment, the armature of the motor revolves, thus revolving the pinion E and gears e e, pinions d d, and gear D, and hence the spindle C. The spring member If is caused to be of a strength such that when the magnetic flux of the motor reaches a certain predetermined degree or amount the magnetic field surrounding the magnetic member M will overcome the resistance of the spring member, attract same toward member M, and thus release the disk I) from its engagement with the handle, and thus allow such disk to be operated by the retractile spring I), so as to throw the contact-segment of the controller into its off position. My invention is so designed that such actuation of the controller to its off position will take place when the resistance to the drilling operation becomes so great that there is effected a flow of current through the motor which is slightly less than the amount which would be injurious to the mechanism. The current is therefore automatically shut off at the proper moment to prevent damage, and neither an inexperienced, careless, nor malicious operative can in any way hold or force the drill to the work over and above its adjusted capacity.

Having described my invention in detail, that which I particularly point out and distinctly claim is- 1. In a portable eleetrically-operated drill, the combination of a multipolar motor provided with a casing and a hollow shaft; a drillspindle mounted in said casing; intermediate gearing connecting said motor-shaft and spindle; and a feed-screw located within said hollow shaft and provided with an end portion projecting therefrom and having a bearing adapted to receive the inner end of said drillspindle.

2. In a portable electrically-operated drill, the combination of a multipolar motor provided with a casing and mounted within the latter and having a hollow shaft; a feedscrew mounted within said shaft and coaxial therewith; a drill-spindle mounted in one end of the casing and having its axis in the same straight line with the motors axis; a remov- 6o able head secured to the other end of said casing; intermediate gearing connecting said motor and spindle; a diaphragm located transversely of said line of the motor-axis, one end of said motor-shaft being supported by said head and the other by said diaphragm; and binding-bolts passing through said head between the separate field-sections and having their inner ends secured to said diaphragm.

3. In a portable electrically-operated drill, the combination of a multipolar motor provided with a casing and mounted within the latter and having a hollow shaft; a feedscrew mounted within and coaxial with said shaft; a drillspindle mounted in one end of the casing and having its axis in the same straight line with the motors axis; a removable head secured to the other end of said casing; intermediate gearing connecting said motor and spindle; a diaphragm located transversely of said line of,the motor-axis, one end of said shaft being supported by said head and the other by said diaphragm; binding-bolts passing through said head and between the separate field-sections and having their inner ends secured to said diaphragm; and a controller for said motor having its resistance-coils mounted upon said bindingbolts.

4. In a portable electrically-operated drill, the combination of a multipolar motor provided with a casing and a shaft; a drill-spindle mounted in said casing; a removable head secured to said casing, provided with a bearing for one end of the motor-shaft, and including an annular ring adjustable around the axis of the motorshaft; brush-holders mounted upon said ring; intermediate gearing connecting said motor and spindle; a diaphragm located transversely of the motor shaft and providing a bearing for the other end of the latter; and binding-bolts passing through said head between the separate fieldsections and having their inner ends secured to said diaphragm.

5. In a portable electrically-operated drill, the combination of a motor provided with a casing and a shaft; a drill-spindle mounted in said casing; gearing connecting said motorshaft and drill-spindle; and a feed-screw located within said casing centrally relatively to said motor and arranged with one end in juxtaposition to the inner end of said drillspindle.

Signed by me this 14th day of September, 1904.

ADOLIII PEDERSEN.

Attest:

D. T. Davms, A. E. MERKEL. 

